Background: Food IgE-mediated allergy to members of the Brassicaceae family has been increasingly reported.
Objective: To characterize cabbage-Brassica oleracea var capitata-allergy and its major allergens.
Methods: A prospective study was performed, recruiting 17 patients allergic to cabbage, and control subjects. Skin prick tests and double-blind placebo-controlled food challenges were performed. A major allergen was isolated from cabbage by RP-HPLC and characterized by N-terminal amino acid sequencing and matrix-assisted laser desorption/ionization mass spectrometry analysis. Specific IgE determinations, IgE immunoblots, and CAP-inhibition assays were also performed.
Results: Skin prick test and specific IgE were positive to cabbage in all patients. Five of them referred anaphylactic reactions when eating cabbage, and in another 5 patients, cabbage allergy was further confirmed by double-blind placebo-controlled food challenge. Most of them showed associated sensitizations to mugwort pollen, mustard, and peach. A 9-kd cabbage IgE-binding protein, Bra o 3, was identified as a lipid transfer protein (LTP) with 50% of identity to peach LTP Pru p 3. Skin prick test with Bra o 3 showed positive results in 12 of 14 cases (86%). On CAP inhibition assays, Bra o 3 managed to inhibit significantly the IgE binding to cabbage, mugwort pollen, and peach. Both Bra o 3 and Pru p 3 were recognized by IgE from the patients' sera.
Conclusion: Bra o 3, a cabbage LTP, is a major allergen in this food, cross-reacting with mugwort pollen and with other plant foods, such as peach.
Clinical implications: Cabbage IgE-mediated allergy is a potentially severe condition that can present with other plant food and pollen allergies.